Units and species
Every concentration in AirDesk is in micrograms per cubic metre, µg/m³, and every species has a
code — so2, pm10 — that is the same in every demo, every file and every screen. What changes
with the language is only how it is written.
The species
Section titled “The species”| Code | Name | Formula | Note |
|---|---|---|---|
so2 |
Sulfur dioxide | SO₂ | Combustion of sulfur-bearing fuels; smelters |
no2 |
Nitrogen dioxide | NO₂ | The nitrogen oxide the standards limit |
no |
Nitric oxide | NO | The precursor; oxidises to NO₂ in air |
nox |
Nitrogen oxides | NOₓ, as NO₂ | The sum, expressed as NO₂ |
pm10 |
Respirable particulate matter | PM₁₀ | Particles up to 10 µm |
pm25 |
Fine particulate matter | PM₂.₅ | Particles up to 2.5 µm |
co |
Carbon monoxide | CO | Incomplete combustion |
voc |
Volatile organic compounds | VOC | A mixture, not a substance: registered, not modelled |
trs |
Total reduced sulfur | TRS, chiefly H₂S | Pulp-mill and refinery odour |
odor |
Odour | ouₑ/m³ | Odour units, not mass |
o3 |
Ozone | O₃ | Secondary; in the standard, not in the forecast |
Which species each demo models is a fact of the demo, not of the registry: this demo’s page says, and the dashboard lists them under Domain → Species.
How they are written
Section titled “How they are written”- PM in English, MP in Spanish. Particulate matter is PM₁₀ and PM₂.₅; in Spanish, MP₁₀ and MP₂,₅ — with a decimal comma, like every Spanish number. The application switches the writing with the language.
- Subscripts are subscripts: SO₂, not SO2; the application typesets them so in every label, and these guides do too.
- The unit is written µg/m³, with the Greek mu and the cube as a superscript. An exported table carries it the same way, which is why the file carries the encoding mark Excel needs to read it.
- Values show with three significant figures — 65.8 · 1.52 · 0.165 —, with the language’s decimal separator.
Normal conditions or not
Section titled “Normal conditions or not”The model delivers µg/m³ at the modelled atmosphere’s conditions. The Chilean standard states its limits in µg/m³N — normal conditions, 25 °C and 1 atm — and the Indonesian one in plain µg/m³. The difference is a few percent and is not corrected in the demo; it is declared here so a comparison with the standard is read with that margin in mind.